1. Field of the Invention
One important factor that affects the production of food worldwide is the amount of sulfur available to plants and the amount of sulfur-containing compounds in plants that are eaten by animals, including humans. Sulfur is an essential element in plant and animal nutrition. Indeed, sulfur is necessary for the activation of some vitamins and enzymes as well as for the formation of certain oils, amino acids, and proteins. Some examples of sulfur-containing amino acids comprise methionine, cysteine, homocysteine, and taurine. Because methionine is not synthesized by humans and animals it is considered an “essential amino acid,” which must be taken up through diet. Additionally, because the level of proteins produced by an animal is often directly linked to the amount of available methionine, and not to the amount of many other amino acids, methionine is considered a “limiting amino acid.” Accordingly, plants and animals that are deficient in sulfur and sulfur-containing compounds, such as methionine, may not be able to produce optimal levels of some proteins. Unfortunately, sulfur deficiencies may be becoming more prevalent.
Alkalinity is another important factor affecting the quality, efficiency, and performance of soil and irrigation water. A relative increase in irrigation alkalinity due to the sodium to calcium ratio or a high pH can render irrigation water and soil detrimental to crop growth and irrigation water efficiency.
The invention of this application is directed toward a device that can both increase the level of sulfur that is available to crops as well as reduce the alkalinity of soil and water by producing a sulfurous acid that can be added to water and soil. Generally, this application discusses a sulfurous acid generator, which generates sulfurous acid in a simple and efficient way. In particular, it is directed toward a sulfurous acid generator that produces sulfurous acid by burning sulfur in a burn chamber that acts as a sulfur hopper. The burning sulfur produces sulfur gases, which include sulfur dioxide. Through the use of a direct inducer, the sulfur gases are then drawn toward and held in contact with water, where the gases eventually react with the water and produce sulfurous acid. The sulfurous acid generator produces this sulfurous acid while substantially reducing dangerous emissions of sulfur gases to the air.
2. The Relevant Technology
There are several sulfurous acid generators in the art. The prior art devices utilize a variety of sulfur hoppers, sulfur burn chambers, and mechanisms for dissolving sulfur gases into water. However, many known systems utilize a hopper that is separate and distinct from the burn chamber; a countercurrent flow, pressurized system; and/or a single eductor arrangement as the principle means to accomplish the generation of sulfurous acid. For example, some devices employ a side-by-side or concentric hopper and burn chamber. Such devices may be large, difficult to move, and costly to produce. Also, some devices use an absorption tower to introduce the majority of the water to the system in flow that runs countercurrent to the flow of sulfur gases, such as sulfur dioxide. U.S. Pat. No. 4,526,771 teaches introducing 90% of the system water for the first time in countercurrent flow at the top of the absorption tower. In such devices, the integrity of the absorption tower is vital, and any deficiencies or inefficiencies of the absorption tower lead to diminished reaction and results. Other devices utilize pressurized gas to facilitate flow of gas through the system. (See e.g., U.S. Pat. No. 3,226,201). Pressurized devices, however, are often expensive to manufacture in a manner that ensures the containment and prevents the leakage of dangerous sulfur gases. Even negative pressure machines tend to have the drawback of requiring a source of energy to power a negative pressure generator, such as an exhaust fan. Still other devices rely upon secondary combustion chambers to further oxidize the sulfur. (See e.g., U.S. Pat. No. 4,526,771). An earlier Harmon device utilized a single eductor in combination with a countercurrent absorption tower. The inventor has himself developed several different sulfurous acid generators. (See e.g., U.S. Pat. Nos. 6,080,368, 6,248,299, 6,500,391, 6,506,347, and 6,689,326). Many sulfurous acid generators emit significant or dangerous levels of unreacted sulfur dioxide gas, a harmful and noxious pollutant, into the surrounding environment. Many devices also discharge a visible plume or cloud.